Heating apparatus for heating dialysis liquid, dialysis liquid tube set, set, medical apparatus and methods

ABSTRACT

A heating apparatus for heating a dialysis liquid includes a receiving section for receiving a heating bag through which dialysis liquid to be heated can flow, and a sensor system for determining or monitoring the deformation or the position of the heating bag in the receiving section of the heating apparatus or both. A dialysis liquid tube set, a set, a medical apparatus and a method are also described.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of and claims priorityunder 35 U.S.C. § 120 to U.S. patent application Ser. No. 13/851,234,filed on Mar. 27, 2013, which claims priority to U.S. ProvisionalApplication Ser. No. 61/616,441, filed on Mar. 28, 2012, and ApplicationNo. DE 10 2012 006 149.8, filed in the Federal Republic of Germany onMar. 28, 2012. Each application is expressly incorporated herein in itsentirety by reference thereto.

FIELD OF INVENTION

The present invention relates to a heating apparatus. It further relatesto a dialysis liquid tube set, a set, a medical apparatus, and a method.

BACKGROUND INFORMATION

International Patent Publication No. WO 2010/025824 A2 describesapparatuses by means of which dialysis liquid is heated by means of aheating bag during a dialysis treatment. Heating takes place while thedialysis liquid flows through the heating bag, before the dialysisliquid is introduced into the dialyzer or blood treatment filter, inwhich substances are exchanged between blood and dialysis liquid viaa—usually semipermeable—membrane.

Under certain operating conditions, it can however not be excluded,without having taken countermeasures, that the heating bag bursts due tothe pressure built up by the pump which conveys the dialysis liquidthrough the heating bag. Bursting could take place especially inarrangements in which the heating bag is arranged on the pressure sideof the pump—for example to avoid precipitations in the tube system.Bursting of the heating bag may pose a danger to the patient, at leastif it is not noticed in time.

SUMMARY

An object of the present invention is to propose apparatuses and methodsto decrease the risk that a heating bag bursts during the dialysistreatment or bursts unnoticed.

Thus, according to the present invention, a heating apparatus isproposed for heating a dialysis liquid which is present in a heatingbag. The dialysis liquid flows during use through the heating bag forbeing heated, or it can flow through it. The heating apparatus comprisesa receiving section for receiving the heating bag. Further, the heatingapparatus comprises a sensor system. The sensor system is at least oneof arranged, provided, designed, configured or programmed fordetermining or monitoring a deformation or longitudinal expansion of theheating bag or the location or position of the heating bag which itoccupies within the heating apparatus or within the receiving section ofthe heating apparatus, or both.

Further, according to the present invention, a dialysis liquid tube setis proposed. The dialysis liquid tube set is provided or designed to beinserted into the heating apparatus according to the present invention.

According to the present invention, a set is furthermore proposed. Theset according to the present invention comprises a heating apparatusaccording to the present invention with at least one receiving sectionfor receiving a heating bag. Further, the set comprises at least onedialysis liquid tube set, which—being preferably integralherewith—comprises at least one heating bag through which the dialysisliquid can flow.

The dialysis liquid tube set or the receiving section of the set—orboth—are chosen, determined or coordinated such that the length of theheating bag is always less than the length of the receiving section ofthe heating apparatus. This way, it is ensured that the receivingsection radially delimits or at least could delimit the heating bag,which is inserted herein, during its use along its entire length. Thismeans that the heating bag or sections hereof cannot leave the interiorof the receiving section even if the heating bag expands—and possiblyexpands till it bursts.

Further, according to the present invention, a medical apparatus isproposed which comprises at least one heating apparatus according to thepresent invention or is connected therewith.

In addition, a method for heating dialysis liquid within a dialysisliquid tube set is proposed. The dialysis liquid tube set comprises aflow-through heating bag for the dialysis liquid to be heated. Themethod encompasses inserting the heating bag in a receiving section of aheating apparatus of a medical apparatus. The method further encompassesselecting—in advance—the utilized dialysis liquid tube set and/or theflow-through heating bag which is present therein. The heating bag andthe receiving section are thereby coordinated or matched such that thelength of the heating bag along which the receiving section surroundsthe heating bag when it is inserted in the receiving section and/orfilled with dialysis liquid is always smaller or less than the length ofthe receiving section.

In all of the following exemplary embodiments, the use of the expression“may be” or “may have,” and so on, is to be understood synonymously with“preferably is” or “preferably has,” respectively, and so on, and isintended to illustrate an exemplary embodiment according to the presentinvention.

Exemplary embodiments according to the present invention may compriseone or more of the features and advantageous developments describedhereafter.

In certain exemplary embodiments of the present invention, the receivingsection is designed to allow a deformation of the heating bag, which isreceived herein, in only one extension direction, due to an interiorpressure of the heating bag.

As an extension direction, in certain exemplary embodiments of thepresent invention, the longitudinal axis of the heating bag or of thereceiving section is understood, wherein an extension is allowed inthese exemplary embodiments in both of the opposite directions of astraight line which is determined by the longitudinal axis. In otherexemplary embodiments of the present invention, an extension ispermitted in only one of the two opposite directions of the straightline.

The sensor system is in certain exemplary embodiments of the presentinvention a purely mechanically acting or functioning apparatus, orboth, which does not comprise electronic elements. In other exemplaryembodiments of the present invention, the sensor system is a purelyelectronically acting or functioning apparatus, or both. In someexemplary embodiments according to the present invention, the sensorsystem comprises at least one of mechanically, electronically oroptically acting or functioning elements.

In certain exemplary embodiments of the present invention, the sensorsystem for monitoring the deformation of the heating bag comprises orconsists of at least one mechanical, one optical sensor, one elementwhich is mounted to be movable, a press key, or arbitrary combinationsof the before-mentioned elements.

In some exemplary embodiments of the present invention, the sensorsystem is designed, arranged or both designed and arranged fordetermining the longitudinal expansion of the heating bag, preferably ofa front end of the heating bag, in particular its head section.

In some exemplary embodiments according to the present invention, thesensor system is neither a weighing device nor comprises such. Weighingdevices may, for example, work according to the principle that a weight,e.g., that of a heating bag, or the change of its weight, is measuredwith a bending beam and strain gages which reflect or detect thedeflection of the bending beam or another change.

In certain exemplary embodiments according to the present invention, thereceiving section is designed such that it encloses the heating bag in acircumferential direction hereof—or in a plane perpendicular to the flowdirection of the dialysis liquid within the heating bag or to thelongitudinal axis of the heating bag—during its use. Thereby, theheating bag is enclosed along its whole length.

“Enclosing” means in some exemplary embodiments of the present inventionthat the receiving section surrounds the heating bag during its usealong the whole circumference of the heating bag or lies flat against itor contacts it. Alternatively, the receiving section surrounds theheating bag not along the whole circumference, but only to an extent ofat least 70%, 80%, 90% or 95%, or the receiving section surrounds theheating bag in radial direction at least such that the heating bag canbe extracted from the receiving section only along its longitudinaldirection, but not in its transverse direction. The latter applies tothe heating bag in a filled condition or in an empty condition orindependent of the filling condition of the heating bag.

In some exemplary embodiments of the present invention, the heatingapparatus is designed to enclose the flow-through heating bag in eachoperating condition cylindrically, sleeve-like or pipe-shaped or lieflat against the heating bag in this way. In doing so, thebefore-mentioned definition of “enclosing” can apply.

The receiving section is in some exemplary embodiments of the presentinvention designed to withstand an inside/internal pressure of theheating bag of 1050 mbar over a period of 72 hours. Further, it has towithstand 10 loading conditions over a period of each 20 seconds with apressure of each 3200 mbar in these exemplary embodiments and isdesigned accordingly.

For receiving the pressures which occur when the heating bag is beingfilled, the wall or limitation of the receiving section is in someexemplary embodiments of the present invention accordingly designed. Forexample, a longitudinal slot of the receiving section, through which thedrain line of the heating bag can be led or fed through when the heatingbag is being inserted (see FIG. 5a ), is limited to a value of a rangefrom 5 mm to 15 mm width, preferably to a value of a range from 8 mm to10 mm, e.g., 8 mm. This design allows the receiving section to withstandthe internal pressure. The actually freely selectable dimension of theopening of the housing of the heating apparatus may be slightly narroweror less than the gap dimension of the cylindrical wall described below.

In some exemplary embodiments according to the present invention, theheating apparatus or the receiving section comprises at least onereinforcing element which is arranged to effect reinforcement of thereceiving section against radially acting pressure from the heating bag.Thus, for example, a cylindrical wall of the receiving section may beprovided at an exterior of the receiving section in radial directionwith one or more, e.g., 2, 3, 4 or more, reinforcing elements such assteel clips or clamps.

In addition or as an alternative to the reinforcing elements mentionedbefore, for reinforcement against mechanical stress by the heating bagthe wall of the receiving section is in some exemplary embodiments ofthe present invention made of ceramics, or it comprises ceramics.

In some exemplary embodiments of the present invention, the sensorsystem of the heating apparatus comprises a sensor which is suitable andused for detecting or recording a longitudinal extension.

In certain exemplary embodiments of the present invention, the sensor ofthe sensor system determines or reports the location of the heating bagrelative to a receiving level or state of the heating bag before itslongitudinal extension. For example, the sensor may determine or reporta later extension of the heating bag based on the later location,position or extension of the heating bag compared to the bag's previouslocation, position or extension.

In certain exemplary embodiments of the present invention, the sensorsystem comprises an element which is provided or mounted to be movable.The element is, for example, designed as a mechanical tactile sensor,and hereafter it is denoted as such in a simplifying but non-restrictiveway. By means of the mechanical tactile sensor, a detected longitudinalextension is signalized in certain exemplary embodiments according tothe present invention in that the mechanical tactile sensor, preferablyin a mechanical or another way, actuates a switch or an apparatus suchas a micro switch. The actuation of this switch or this apparatusdirectly or indirectly leads to the consequences of the alarm asdescribed herein, such as a stopping of the pump, a slowdown of the pumpor other suitable measures.

In some of these exemplary embodiments according to the presentinvention, the heating apparatus further comprises an additionalchecking apparatus which is arranged for testing, when being actuated,the correct function of the sensor system, the movably mounted elementsuch as for example the mechanical tactile sensor, the switch and/or theapparatus singularly or in arbitrary combinations. For example, thechecking apparatus is in some exemplary embodiments of the presentinvention designed as a mechanical or hydraulic element which isarranged for actuating the switch, for example the micro switch, likethe mechanical tactile sensor, but independent hereof, or it comprisessuch an element. By actuating the checking apparatus, it is possible totest the function of the switch.

In some exemplary embodiments of the present invention, the checkingapparatus is arranged to act on the mechanical tactile sensor or to moveit such that it actuates the switch on his part. With the checkingapparatus being arranged this way, it is possible to check both thefunction or movability of the mechanical tactile sensor and the functionof the switch when the checking apparatus is being actuated for testreasons.

A performance test for the switch—with or without testing the mechanicaltactile sensor at the same time—can take place automatically and, forexample, every time the heating apparatus is being started.

The checking apparatus may comprise or consist of a lifting magnet orsolenoid and a rotating element. The solenoid is advantageously suitableto be actuated in a contact-free way also from an exterior of theheating apparatus. The rotating element allows to act on the mechanicaltactile sensor in a space-saving way, by means of the solenoid, or in adifferent way.

In some exemplary embodiments of the present invention, the rotatingelement transfers a linear movement of a first element, e.g., a bar, asolenoid or a ram or piston, to a second linear element. The rotatingelement and the two linear elements can be in one level. The rotatingelement can be arranged on an axis or shaft to be rotatable, for exampleon a pin on which the rotating element is mounted to be rotatable (e.g.,by means of a slide bearing).

The second linear element can be the tactile pin. The rotating elementcan engage in or with the tactile pin to move it when the rotatingelement rotates.

In some exemplary embodiments of the present invention, the rotatingelement is designed to be able to move the tactile pin during a rotation(in that the rotating element for example contacts a stop of the tactilepin), without being moved itself if the tactile pin is moved by anotherelement than the rotating element.

In some exemplary embodiments of the present invention, the deformationor longitudinal expansion of the heating bag in axial direction is ameasure for the material stress of the heating bag or it is—inparticular completely or essentially completely—a result of it.Monitoring the longitudinal expansion of the heating bag can allow aconclusion on the material stress in the moment of monitoring. Thematerial stress can be compared with values that were previouslyrecorded. If admissible limit values for material stress, which aremostly recorded or saved, are reached or exceeded, an alarm can beoutput or the operation of an apparatus, for example the pump, by meansof which the heating bag is filled, can be stopped or slowed down.

In some exemplary embodiments of the present invention, the heatingapparatus comprises an apparatus for outputting an alarm or an apparatusfor stopping or slowing down a pump which conveys the dialysis liquidthrough the heating bag, or both. Thereby, the apparatuses areconfigured, set up or programmed for outputting an alarm or for stoppingthe pump, if or when the sensor system detects a predetermineddeformation of the heating bag, a predetermined location of the heatingbag in the receiving section, a predetermined material stress orarbitrary combinations hereof.

In certain exemplary embodiments of the present invention, a dialysisliquid tube set or system is inserted into the heating apparatus. Thedialysis liquid tube set comprises—preferably manufactured integrallywith the tube set—at least one heating bag. The heating bag is providedfor herein heating dialysis liquid from the dialysis liquid tube set bythe heating apparatus.

The explanations made herein with respect to the dialysis liquid applyin certain exemplary embodiments of the present invention also tosubstituate. Also, the explanations made here with regard to dialysisliquid tube sets apply in certain exemplary embodiments of the presentinvention also to substituate tube sets.

In some exemplary embodiments according to the present invention, thedialysis liquid tube system is designed as a one-way product ordisposable.

In some exemplary embodiments according to the present invention, thedialysis liquid tube system is a dialysis liquid tube.

In some exemplary embodiments of the present invention, the medicalapparatus comprises an apparatus for monitoring a correct arrangement ofthe heating bag in the receiving section, or for monitoring that thelongitudinal expansion of the heating bag does not exceed a predefinedlimit value, or both. The medical apparatus further comprises anapparatus for outputting an alarm or an apparatus for stopping orslowing down a pump which conveys the dialysis liquid through theheating bag, or both.

In certain exemplary embodiments of the present invention of the medicalapparatus, it is designed as a blood purification device, for example asa dialysis apparatus, as a filtration apparatus, as a diafiltrationapparatus, or as a dialysis apparatus in any other exemplary embodimentfor blood purification which is known to the person skilled in the art.

The medical apparatus is in certain exemplary embodiments according tothe present invention configured for use for the continuous venoushemodiafiltration (CVV-HDF) and/or configured for use for acutedialysis.

In certain exemplary embodiments according to the present invention, themedical apparatus according to the present invention is connected withan extracorporeal blood circuit and/or a tube system.

In certain exemplary embodiments of the present invention, itencompasses inserting the heating bag such that a front end of theheating bag rests on or is in contact with a bottom section of thereceiving section when being inserted or due to inserting. This way, itis ensured that the heating bag can expand or extend only in onedirection along its longitudinal direction, namely away from the bottomsection, but not towards it.

A heating bag is in some exemplary embodiments of the present inventionthe section of a dialysis liquid tube set, which by being filled isdilated according to its intended use or can be filled under its radialexpansion.

A heating bag is in certain exemplary embodiments of the presentinvention the section of a dialysis liquid tube set which has a thinnerwall thickness than adjacent tube sections.

A “flow-through” heating bag is in some exemplary embodiments of thepresent invention a heating bag which comprises an inlet and at leastone supply line which is connected herewith. The heating bag furthercomprises a drain which is separate from at least one drain line whichis connected herewith. Thereby, the supply line or the drain line, orboth, each have a diameter which does not correspond to a maximumdiameter of the heating bag during use.

In some exemplary embodiments of the present invention, the extensiondirection or expansion direction of the heating bag is the direction inwhich the flow streams during use. In certain exemplary embodiments,this is the direction of its longitudinal axis or longitudinalextension. Wherever herein a direction or axis is mentioned, anexpansion in one direction or in both (opposite) directions along theextension or axis can be meant.

The length of the heating bag is in some exemplary embodiments of thepresent invention understood to be a longitudinal extension of theheating bag, which it can assume during use. In certain exemplaryembodiments of the present invention, the length is understood to be thelongitudinal extension of the heating bag which the heating bag canassume as a maximum before it bursts if its radial expansion isprevented or limited in that the whole heating bag radially contacts orlies flat or could contact or lie flat against the receiving section.

The length of the receiving section of the heating apparatus is incertain exemplary embodiments of the present invention understood as thedimension of the receiving section in its longitudinal directionwhile—preferably completely or essentially—the cross-section or innercircumference of the receiving section along which the heating bagcontacts or could contact does not change even if or when it expands dueto increasing internal pressure in the bag.

“Determining” or “monitoring” as used herein can be or encompasschecking or detecting whether a sensor recognizes the presence of asection of the heating bag at a predetermined spot of the receivingsection or the heating apparatus.

In some exemplary embodiments according to the present invention,“determining” or “monitoring” as used herein means not solelydetermining, monitoring or checking whether a heating bag is insertedinto a receiving section or a heating apparatus. “Solely” can beunderstood herein as a digital condition. It is determined, monitored orchecked, for example, whether a heating bag is inserted into a receivingsection or a heating apparatus at all (‘Yes’) or is not inserted (‘No’).In these exemplary embodiments, “determining” or “monitoring” also meansor encompasses identifying where the heating bag or a section thereof ispresent.

In certain exemplary embodiments according to the present invention,“determining” or “monitoring” as used herein means determining,monitoring or checking whether a heating bag has been inserted into areceiving section or a heating apparatus at all, or not (for example itspresence is verifiable at a certain location or position), but not atwhich location or position inside of the heating apparatus the heatingbag is present.

“Determining” or “monitoring” may take place metrologically, and thesensor system can be accordingly designed.

In some exemplary embodiments according to the present invention, theheating apparatus comprises at least one fixation device for fixing thelower tube section (or a section thereof) at the heating apparatusand/or for restraining device for assuring that the lower end of the bagin its intended or predetermined use is arranged at the lower end of theheating apparatus and/or remains there.

For example, the heating apparatus can have, e.g., at its front side, aclamping device into which a section of the lower tube section, which isguided to an outside through the slot of the front side, is clamped—orfixed in any other way than clamping. For creating a form closure and/ora traction or force closure between the lower tube section and theheating apparatus, e.g., the front side thereof, can be provided.

To this end, the vertical or longitudinal slot can, in a preferredexemplary embodiment according to the present invention, be lead (e.g.,for a short distance) upwardly ascending in a U shaped manner at itslower end, for example by a multiple of the diameter of the tube of thelower tube section. Hereby the lower tube section can be upwardlyredirected once the heating bag has been correctly inserted. Theclamping device can thereby optionally advantageously act as strainrelief, by which the redirected tube section can be securely set orfixed.

Additionally or alternatively, the lower tube section can comprise arestraining element (e.g., a plastic sleeve, e.g., with at least oneledge or edge at or around its circumference). The restraining deviceallows for a form locking setting or arrangement of the lower tubesection on the heating apparatus (e.g., at the slot, at the clampingdevice, if provided, etc.). The clamping device, if provided, can herebyact as abutment and absorb the tensile or tractive forces acting on thetube.

Alternatively or additionally, in some exemplary embodiments accordingto the present invention, a frictional fixation or restraining or forceclosure is achieved or provided by a half-open (half-pipe) orlongitudinally slotted, trough shaped tube guiding element into whichthe lower tube section is pushed under elastic deformation and is,thereby, frictionally set or fixed.

Some or all exemplary embodiments according to the present invention mayprovide for one, several or all of the advantages named above and/orhereafter.

An advantage according to the present invention is that a bursting ofthe heating bag due to high internal pressure can be prevented since itis supported by the receiving section along its whole length radially orin circumferential direction—and even after expansion of the heatingbag. An expansion of the heating bag is thus at most possible in itslongitudinal direction. A local overstress and uneven stress of theheating bag is thus prevented.

Another advantage which is achievable by means of the present inventionis that by the sensor system a control can take place whether theheating bag was correctly inserted. Further, it can be monitored by thesensor system that the heating bag cannot expand or extend beyond apredefined degree unnoticed. As such expansion would be recognized bythe sensor system, required measures can be taken in time.

Yet another advantage of the present invention may be that thefunctionality of the sensor system can be checked by the checkingapparatus in a simple and reliable way. This may take place separatelyor together for the mechanical tactile sensor and the switch or acorresponding apparatus.

The checking apparatus may hereby be provided in constricted or limitedspace. It may be actuated touchlessly from outside the heatingapparatus.

In some exemplary embodiments according to the present invention, anadvantage can be found in that during use the heating bag is insertedinto the heating apparatus reliably completely down to its end or stop.Moreover, in certain exemplary embodiments according to the presentinvention, after the correct insertion of the heating bag, the heatingbag cannot accidentally be pulled out during the further set up of thetube set at the medical apparatus such that the lower end of the bag isno longer set at the lower end of the heating apparatus. This can alsobe advantageously prevented by exemplary embodiments according topresent invention.

Exemplary embodiments of the present invention are hereafter describedwith reference to the appended drawings, in which identical referencenumerals refer to same or similar components.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 schematically shows in a section view a heating apparatusaccording to the present invention with a heating bag and a sensorsystem for detecting the heating bag.

FIG. 2 shows a detail of the heating apparatus according to the presentinvention from FIG. 1.

FIGS. 3a and 3b schematically show the sensor system from FIG. 2 in anon-activated or an activated test position.

FIG. 4 schematically shows the principle of a light barrier fordetecting the heating bag according to the present invention.

FIGS. 5a to 5d schematically show a cylindrical wall of the heatingapparatus, partially with reinforcing elements.

FIGS. 6a to 6g show in a schematically simplified way variants forreceiving the heating bag in the heating apparatus according to thepresent invention in a pressure-resistant way.

FIG. 7 schematically shows a medical apparatus according to the presentinvention for dialysis, with an extracorporeal blood circuit, a heatingapparatus according to the present invention and a dialysis liquid tubeset.

DETAILED DESCRIPTION

FIG. 1 schematically shows in a section view a heating apparatus 100according to the present invention with an inserted heating bag 1. Theheating bag 1 comprises an upper tube section 3 as supply line and alower tube section 5 as drain line (or vice versa), which can beconnected or which is connected with a tube set 700, 800 (see FIG. 7).

Furthermore, the heating apparatus 100 comprises a sensor system 300adapted for detecting an expansion of the heating bag 1, e.g., caused byan increased fluid internal pressure, in longitudinal direction (seealso FIG. 2 for the sensor system 300).

The heating bag 1 is almost completely enclosed by the heating apparatus100 in radial circumferential direction. Only a longitudinal slot 6remains as an opening on the front side 7 of the heating apparatus 100.Through the longitudinal slot 6, the lower tube section 5 can be pushedthrough into a receiving section 8 which is located behind thelongitudinal slot 6, in order to be able to readily introduce or insertthe heating bag 1 into the heating apparatus top-down. The longitudinalslot 6 is embodied according to FIGS. 6a to 6e .

If the dialysis liquid flows through the heating bag 1, either throughthe upper tube section 3 as fluid inlet or supply line and the lowertube section 5 as fluid outlet or drain line, or vice versa, thedialysis liquid is heated in a controlled manner by the heatingapparatus 100.

In the illustration of FIG. 1, the heating bag 1 can only expand upwards(related to FIG. 1) and thus in its longitudinal extension, as theheating bag 1 is limited by the wall of the receiving section 8 inradial or in circumferential direction along its whole length andbeyond. In addition, the heating bag 1 is limited with its lower faceend or foot by a bottom section 8 a. The bottom section 8 a isrecognizable in FIG. 1 as domed. It is thus recreated to the shape ofthe heating bag 1 in its filled condition or copies the same. Any othershape of the bottom section 8 a is however also encompassed by thepresent invention.

The present invention comprises in some exemplary embodiments arestraining device, which is not shown in the figures, for assuring thatthe lower end of the bag, during its intended or predetermined use, isset at the lower end of the heating apparatus and/or remains there.

By way of example, the lower end of the heating bag 1 may be set at thelower end of the heating apparatus 100, by setting or fixing the lowertube section 5, which is guided out of the slot 6 from the front side ofthe heating apparatus 100, at or to the front side 7 of the heatingapparatus 100 by form closure and/or traction, in a defined orpredetermined manner. To this end, in a preferred exemplary embodiment,the vertical slot 6 can be guided or lead (e.g., by a short distance)upwardly, ascending in a U-shaped manner at its lower end, for exampleby a multiple of the diameter of the lower tube section 5. Hereby thelower tube section 5 can be upwardly redirected once the heating bag 1has been correctly inserted, wherein a clamping device provided, e.g.,at the front side 7 of the heating apparatus 100, can act as strainrelief, by which the redirected tube section 5 can be securely set orfixed at the front side 7 of the heating apparatus 100.

Additionally or alternatively, the lower tube section 7 can comprise arestraining or fixation element which is not shown in the figures (e.g.,a plastic sleeve, e.g., with at least one ledge or edge, arranged on oraround its circumference) which allows for a form locking setting of thelower tube section onto the clamping device, wherein the clamping devicecan hereby act as an abutment and absorb the tensile or tractive forcesacting on the tube.

Alternatively or additionally, in some exemplary embodiments accordingto the present invention, a frictional fixation or restrainment isprovided by means of a half-open or longitudinal slotted, trough shapedtube routing or guiding element, into which the lower tube section 5 ispushed under elastic deflection and thereby is frictionally set orfixed.

FIG. 2 shows a detail of FIG. 1 with a sensor system 300 to detect theheating bag 1 or its location within the receiving section 8.

In the initial position, the heating bag 1 in the receiving section 8 isin position y0. There is no overpressure in the heating bag 1. Theposition y0 is where the heating bag 1 just barely still has contactwith the inner side 9 of the receiving section 8. If the fluid pressurerises, the heating bag 1 expands. This expansion and its direction isindicated in FIG. 2 by three parallel arrows. A rising fluid pressurecan be caused by an increased fluid resistance downstream from theheating apparatus 100, for example by an increased filter resistance, orby an increased fluid pressure upstream. Due to the increasing fluidpressure, the heating bag 1 expands for example such that it still hascontact with the inner side 9 up to position y1. If the fluid pressureincreases even further, the heating bag 1 has contact with the innerside 9 up to position y2 or possibly even higher.

At position y2, the sensor system 300 of the heating apparatus 100according to the present invention comprises a sensor which in thisexemplary embodiment is an element in the form of a tactile pin 11,which is arranged to be mechanically movable, and a micro switch(tactile pin 11 with micro switch are also denoted as mechanical tactilesensor). Once the expansion of the heating bag 1 has reached theposition y2, and if the heating bag 1 in the position y2 still hascontact with the inner side 9, the heating bag 1 moves the tactile pin11 in the direction of the horizontal arrow. Consequently, the microswitch (not described in more detail here) is activated, which can forexample output an electric signal.

The tactile pin 11 can be completely moved (or pressed) to a stop 13.The stop can prevent a tilting of the tactile pin 11. Further, a spring14 for pre-stressing or returning the tactile pin 11 can be provided.

The micro switch may output a signal, which in turn can trigger an alarmin a connected processing and/or control unit for reporting a fault. Bythe alarm, suitable counter-measures can be initiated. For example, thepump filling the heating bag can be stopped or slowed down in order toprevent a bursting of the heating bag 1 due to continuing pumpperformance.

The alarm indicates that a predetermined limit value of a longitudinalexpansion or of a limit position of the heating bag 1 has been reachedand/or exceeded. The limit value is in this case exceeded at positiony2. In the exemplary embodiment shown here, position y2 is 20 mm awayfrom position y0, and position y1 is 10 mm away from position y0. Thelimit value y2 thus indicates a maximum admissible deformation of theheating bag 1, before measures are taken or at least an alarm takesplace.

The sensor system 300 can furthermore be used for controlling thelocation of the heating bag 1. For example, an incorrectly insertedheating bag can be detected as the sensor system 300 is activated by theheating bag 1 already before the heating bag 1 has been filled or beforethe dialysis treatment has been started.

FIGS. 3a and 3b schematically show the sensor system 300 from FIG. 2 ina non-activated (FIG. 3a ) or an activated (FIG. 3b ) test position.

Before the heating apparatus 100 is being used, the sensor system 300can be tested with respect to its function (so-called “self-test”). Thisis in particular relevant if the tactile pin 11 with the micro switch isa safety-relevant protective device of an overall system. Thereby, ifpossible, not only the micro switch should be checked, but also theactivation of the micro switch by the tactile pin 11. A manual actuationof the tactile pin 11 by the user is not considered to be useful and maymoreover be forgotten. Hereinafter, a mechanism for such a test isdescribed, which can also be performed automatically.

For the self-test, a checking apparatus is provided. In the example ofthe Figures, it comprises a solenoid 15 and a rotating element 17. Inexemplary embodiments other than the one shown here, it is sufficient toprovide only a magnet but not also a rotating element. The magnet wouldthen pull the tactile pin 11 towards the micro switch.

In the illustration of FIG. 3 however, the solenoid 15, which iscontrolled or activated from outside, controls the tactile pin 11 via arotating element 17. The tactile pin 11 is then moved, limited by thestop 13. In doing so, the micro switch is actuated through the tactilepin 11 and triggers a signal, as described above.

In FIG. 3b , the movements of the tactile pin 11, the solenoid 15 andthe rotating element 17 during the functional test are indicated bymeans of three broken lines. The linear movement directions of thetactile pin 11 and the solenoid 1 are in an angle to each other whichhere is, for example, 90°. The transfer of the movement of the solenoid15 to the tactile pin 11 thereby takes place by the rotating element 17.The angle which is thus possible between the movements of the twoelements 11 and 15, which does not have to be 90° but can also be largeror smaller than 90°, allows for a space-saving arrangement of thechecking apparatus. It can, for example as shown here, be parallel tothe longitudinal extension of the receiving section 8 and be arranged tobe closely mounted or arranged to it.

FIGS. 3a and 3b readily show, especially when being compared with eachother, that during its rotation the rotating element 17 drives thetactile pin 11. The rotating element 17 is, however, designed such thatthe tactile pin 11 can be moved independently from a rotation of therotating element 17.

FIG. 4 shows in a schematically simplified way a reflected light barrier400 for detecting the heating bag 1 in a heating apparatus 100.

The reflected light barrier 400 can be used as an alternative (or inaddition as a further safety device) to the sensor system 300 shown inFIGS. 1 to 3 with tactile pin 11 and micro switch for detecting theheating bag 1. The reflected light barrier 400 may be used at the sameposition of the receiving section 8 as the sensor system 300.

With the aid of the reflected light barrier 400, both an initiallyincorrectly inserted heating bag 1 and a heating bag 1 which is expandedtoo much can be detected—as with the exemplary embodiment shown in FIGS.2 and 3.

Furthermore, it is, analogous to the function tests described in FIG. 3,possible before use of the heating apparatus 100 to check the reflectedlight barrier 400 initially before use. In this initial test, thesensitivity of the reflected light barrier 400 is set to its maximumvalue with the aid of a switch and a software program (neither of whichis described or shown here). For example, the range of the light barrier(maximum distance of a detected object) may be at least 33 mm, in orderto bridge an interior space of a cylinder of the heating apparatus 100.The light 21 emitted by a light source, for example an infrared (IR)diode 19, is analyzed and evaluated at the opposite side of thecylinder. Alternatively, it is reflected at a reflector 23, as shown inFIG. 4. If the light 25 reflected by the reflector 23 can be reabsorbedby the reflected light barrier 400 with the aid of a suitable apparatussuch as for example a photodiode 27 (or a phototransistor), and acorresponding voltage signal can be read by the photodiode 27, thefunctional test is considered to be passed, and the reflected lightbarrier 400 can be used to detect the heating bag 1 in the heatingapparatus 100. This mode for testing in which a maximum value of thesensitivity or range is set or pre-set, is denoted herein as test modefor the light barrier.

If a heating bag 1 is inserted in the heating apparatus 100, thesensitivity or the range of the reflected light barrier 400 is beingreduced by means of the software program. In this case, the light 21emitted by the IR diode 19 should detect neither the opposite reflector23 nor the tube section 3 or the tube section 5 but exclusively the wallof the heating bag 1. The range of the reflected light barrier 400 couldbe set to, for example, about 5 mm for this purpose.

With the such reduced range, the heating bag 1 is not detected duringfailure-free operation, i.e., without increased fluid pressure, becauseit is below the reflected light barrier 300 (with respect to FIG. 4).The tube section 3 or the tube section 5 is also not detected as it isabove (“above” relates to the figures and stands for the direction ingeneral in which the heating bag is allowed to expand within the heatingapparatus 100 according to the present invention) the decreased range,for example about 15 mm away from the reflected light barrier 300. Theouter wall of the heating bag 1 could however be detected by thereflected light barrier 300 if the fluid pressure of the heating bag 1is increased and the heating bag 1 is therefore expanded thus at thelevel of the reflected light barrier 300.

This applies both to an initially incorrectly inserted heating bag 1 andto a heating bag 1 which expanded during its use due to an increasedfluid pressure and/or an increased temperature of the fluid. This mode,in which a small sensitivity or range for detecting the heating bag 1 isset, is denoted as operating mode or treatment mode of the lightbarrier.

The operating mode can also be used to initially identify if a heatingbag 1 of a previous use or treatment is still inserted. This test couldbe performed directly after the actual initial test (test mode).

FIGS. 5a to 5d schematically show a cylindrical wall 29 of the receivingsection 8 of the heating apparatus 100 with different numbers ofreinforcing elements 31.

The cylindrical wall 29 may be a pipe with a radial slot 6 inlongitudinal direction, as illustrated in FIG. 5 a.

The cylindrical wall 29, hereafter denoted as wall 29, is an integralpart of the heating apparatus 100. The wall 29 can be integrated intothe housing of the heating apparatus 100, for example a plastic or resinhousing. The wall 29 surrounds the receiving section 8 and in this wayessentially the heating bag 1 which is inserted in the heating apparatus100. The wall 29 prevents expansion of the heating bag 1 in radialdirection, in particular under fluid overpressure in the heating bag 1.Depending on the stiffness of the wall 29, the wall allows only ormainly an expansion of the heating bag 1 in its longitudinal direction(see FIG. 1: the expansion of the heating bag 1 takes place upwards inlongitudinal direction).

The material of the wall 29 may be or comprise ceramics, e.g., Rubalit.The material may be or comprise a synthetic material (e.g., polyvinylchloride (PVC)), or it may be a different material.

The reinforcing elements 31, if provided, serve for reinforcing the wall29, in particular for increasing the stiffness of the wall 29. Inparticular with a synthetic wall 29, the at least one reinforcingelement 31 can increase the stiffness notably.

The arrangement and the number of reinforcing elements 31 around thewall 29 may differ. In FIGS. 5b and 5d , exemplary arrangements andnumbers of reinforcing elements 31 are shown without being understood tolimit the present invention thereto. In FIG. 5b , the wall is providedwith two reinforcing elements 31, in FIG. 5c with three reinforcingelements 31, and in FIG. 5d with four reinforcing elements 31. More orless reinforcing elements than shown here may also be provided accordingto the present invention. The reinforcing elements 31 may be made ofmetal, for example steel, or of a different material.

The reinforcing elements 31 may be between 1 mm and 5 mm thick, forexample 2 mm.

The reinforcing elements may be rib-shaped. In particular, they may bearranged with a main extension direction which is perpendicular to thelongitudinal direction of the receiving section.

The cylindrical wall 29 of the receiving section 8 of the heatingapparatus 100 may be designed as a separate element, but it may also bedesigned to be integral with the heating apparatus 100. The cylindricalwall 29 may for example be designed as a sleeve, in particular as aretro-fittable sleeve.

FIGS. 6a to 6g show in a schematically simplified view differentvariants for pressure-resistant reception of the heating bag 1 in theheating apparatus 100.

In FIG. 6a , the heating bag 1 is fixed in the heating apparatus 100 bya side door 33 and a cover 35 which is integrated in this door for theupper part of the heating bag 1. Under increased fluid pressure insidethe heating bag 1, an expansion of the heating bag 1 in radial directionof the heating bag 1 is prevented or at least restricted by means ofthis fixation.

In FIG. 6b , the heating bag 1 is fixed in the heating apparatus 100 bya flap 37 which is turned down from above.

In FIG. 6c , the heating bag 1 is fixed in the heating apparatus 100 bya slide 39 which is movable in the longitudinal direction of the heatingapparatus 100.

In FIG. 6d , the heating bag 1 is fixed in the heating apparatus 100 bya pivoting slide 41 or a rotary slide.

In FIG. 6e , the heating bag 1 is fixed in the heating apparatus 100 bya cover 43.

In FIG. 6f , the heating bag 1 is fixed in the heating apparatus 100(not illustrated here) by a clip 45 which is mounted or arranged at theheating bag 1.

In FIG. 6g , the heating bag 1 is fixed in the heating apparatus 100(not illustrated here) by means of a net 47 which is put around theheating bag 1.

FIG. 7 schematically shows a medical apparatus 500 according to thepresent invention (also denoted as treatment system) for dialysis, withan extracorporeal blood circuit 600, a substituate tube set 700 and adialysis liquid tube set 800.

By an arterial connector 49 of an arterial line of the extracorporealblood circuit 600, blood is taken from the patient. Downstream from thearterial connector 49, a shut-off valve 51 is optionally arranged.Further downstream herefrom, the arterial pressure is optionallymeasured by means of a pressure sensor 53, and even farther downstream,a blood pump 55′ is arranged. Between the blood pump 55′ and theconnector of the arterial line to the dialyzer 57, the hemofiltrationpressure is optionally measured by a pressure sensor 59. Downstream fromthis pressure sensor 59, heparin is optionally added to the blood foranticoagulation purposes at an addition point 61.

In the dialyzer 57, the exchange of substances takes place with thedialysis liquid of the dialysis liquid tube set 800, which leaves thedialyzer 57 as dialysate. This is explained in more detail fartherbelow.

Downstream from the dialyzer 57, the blood flows into an optionallyprovided venous drip chamber 63 in which the venous pressure is measuredby means of an optionally provided pressure sensor 65. Downstreamherefrom, a shut-off valve 67 is optionally arranged. The blood isreturned into the vascular system of the patient by a venous connector69.

The substituate tube set 700 serves to substitute to the patient a partof the liquid volume which was extracted from the blood by thefiltration in the dialyzer 57 during the treatment. For this,substituate liquid is taken from a bag 71 or 71′, from which also thedialysis liquid may be sourced or provided. The substituate is conveyedin the substituate tube set 700 by means of a substituate pump 55″ intoa heating apparatus 100′ and heated there, and subsequently added to theblood circuit 600.

The dialysis liquid tube set 800, which may be provided as a one-waytube system (“disposable”), is filled with a dialysis liquid from a bag71. The dialysis liquid is conveyed in the dialysis liquid tube set 800by a pump 55 which is here only exemplarily designed as a roller pump.In doing so, the dialysis liquid from the bag 71 can flow between thebag 71 and the heating apparatus 1 which is located downstream from thepump 55, i.e., on the pressure side of the pump 55, by gravity and/or bysuction of the pump 55. In the heating bag 1, the dialysis liquid isheated by the heating apparatus 100 according to the present invention.

Due to the fluid pressure which is built up by the pump 55, a pressureof approx. 50 mbar may arise in the tube system downstream from the pump55 during the treatment of the patient. This pressure may increase to1050 mbar during a treatment. If the flow is blocked through the tubesystem located downstream, for example due to a corresponding conditionof the filter, a maximum pressure of 3200 mbar can be reached.

Farther downstream from the pump 55 and downstream from the heatingapparatus 1, the dialyzer 57 is arranged. Downstream from the dialyzer57, the filtrate pressure is optionally measured by a pressure sensor73, farther downstream, the dialysate is conveyed into a collectioncontainer 75 together with the filtrate by a pump 55′″, or it isdiscarded.

1. A heating apparatus for heating a dialysis or substituate liquid, theheating apparatus comprising: a receiving section for receiving aheating bag through which the dialysis or substituate liquid can flowfor being heated, the receiving section configured for allowing thedeformation of the heating bag due to an interior pressure of theheating bag in only one extension direction of the heating bag; a sensorsystem for determining or monitoring a deformation of the heating bag ora location of the heating bag along the receiving section of the heatingapparatus; and an additional checking apparatus that is arranged andoperative for automatically performing a self-test of the sensor system.2. (canceled)
 3. The heating apparatus according to claim 1, wherein theheating apparatus or the receiving section comprises at least onereinforcing element which is arranged for effecting a reinforcement ofthe receiving section against a radially acting pressure of the heatingbag.
 4. The heating apparatus according to claim 1, wherein the heatingapparatus is configured for enclosing the flow-through heating bag withrespect to a circumferential direction of the heating bag along a wholelength of the heating bag, and wherein the whole length of the heatingbag is less than a length of the receiving section.
 5. The heatingapparatus according to claim 1, wherein the receiving section isarranged for cylindrically enclosing the heating bag.
 6. The heatingapparatus according to claim 1, wherein the sensor system for monitoringthe deformation the heating bag comprises at least one mechanical or oneoptical sensor.
 7. The heating apparatus according to claim 1, furthercomprising: an apparatus for outputting an alarm or for stopping a pumpwhich conveys the dialysis or substituate liquid through the heatingbag, wherein the apparatus is configured for outputting the alarm or forstopping the pump if or when the sensor system determines the heatingbag is at a limit position along an upper portion of the receivingsection.
 8. (canceled)
 9. The heating apparatus according to claim 1,further comprising: a dialysis or substituate liquid tube set configuredto be inserted in the heating apparatus and comprising at least oneheating bag configured for heating the dialysis or substituate liquid inconjunction with the heating apparatus.
 10. A dialysis liquid tube setconfigured to be inserted in the heating apparatus according to claim 1,wherein the dialysis liquid tube set comprises a flow-through heatingbag having a length that is less than a length of the receiving sectionof the heating apparatus.
 11. A set, comprising: the heating apparatusaccording to claim 1, which comprises the receiving section for theheating bag; and at least one dialysis liquid tube set configured to beinserted in the heating apparatus, wherein the dialysis liquid tube setcomprises a flow-through heating bag having a length that is less than alength of the receiving section of the heating apparatus. 12.-16.(canceled)
 17. The heating apparatus according to claim 1, wherein thechecking apparatus comprises a solenoid arranged to activate the sensorsystem.
 18. The heating apparatus according to claim 1, wherein thechecking apparatus comprises a magnet arranged to activate the sensorsystem.
 19. The heating apparatus according to claim 1, wherein thesensor system comprises a switch, and wherein an activation of thechecking apparatus causes the switch to be activated to thereby triggera signal from the switch that indicates the sensor system is functional.20. The heating apparatus according to claim 1, wherein the sensorsystem comprises a tactile pin positioned along an upper portion of thereceiving section, and wherein the tactile pin is arranged to becontacted by the heating bag as the heating bag deforms along the upperportion of the receiving section.
 21. The heating apparatus according toclaim 20, wherein the sensor system further comprises a switch, andwherein an activation of the checking apparatus causes the tactile pinto activate the switch and thereby trigger a signal from the switch thatindicates the sensor system is functional.
 22. The heating apparatusaccording to claim 20, wherein the sensor system further comprises aswitch, wherein the checking apparatus comprises a solenoid, and whereinan activation of the checking apparatus causes the solenoid to move thetactile pin to activate the switch and thereby trigger a signal from theswitch that indicates the sensor system is functional.